Marking pattern, photomask, photomask inspection method, and medium

Abstract

The present disclosure relates to a mark pattern for being arranged in a cutting path of a photomask, comprising a first mark pattern, a second mark pattern and a third mark pattern arranged in sequence along a first direction; the first mark pattern and the second mark pattern are located at opposite sides of a die area along the first direction at an edge of the photomask, used for defining a length of the die area along the first direction, and the first mark pattern is located in a peripheral area of the photomask; the third mark pattern is located between adjacent die areas along the first direction with the second mark pattern, and used for defining a spacing between adjacent die areas along the first direction. By using the photomask provided by the present disclosure, the accuracy and efficiency of dividing the die area of the photomask can be improved, the machine can smoothly perform defect detection, the situation of missing detection of defects on the photomask can be avoided, and the economic cost, time cost and manpower cost of the enterprise can be saved.

Description

Technical Field

[0001] This disclosure relates to the field of semiconductor technology, and in particular to a marking pattern, a photomask, a photomask detection method, and a medium. Background Technology

[0002] A photomask is a carrier for image transmission. A designed circuit pattern is exposed onto photosensitive emulsion using an electronic laser device. The exposed area is developed to form the circuit pattern, becoming a mask similar to a negative after exposure. This mask is then used to project and position integrated circuits, and the projected circuit is photo-etched using an integrated circuit lithography machine. However, various defects inevitably form during the fabrication process of the photomask, necessitating inspection equipment to check the photomask.

[0003] When inspecting photomasks, a photomask design layout needs to be established to divide the photomask into several bare wafers. Each wafer then undergoes defect inspection. Traditionally, defining the edge positions of the wafers during wafer division is done manually. This can lead to inaccurate edge definitions, making it difficult to completely divide the photomask into the preset size and quantity. This results in machine testing malfunctions, inaccurate detection of defects on the photomask, and economic losses for the company. Furthermore, the definition of wafer edge positions varies for different photomasks, and wafer edge positions are inherently difficult to distinguish, ultimately causing time and wasted human resources for the company. Therefore, there is an urgent need to provide a more efficient wafer division method to improve the accuracy of wafer edge position definition during photomask inspection and avoid economic, time, and human resource losses for the company. Summary of the Invention

[0004] Therefore, it is necessary to provide a marking pattern, photomask, photomask detection method and medium to address the issues of inaccurate definition of the die edge position and low efficiency in traditional technologies. This would improve the accuracy of die edge position definition during photomask detection, enabling the machine to accurately detect defects on the photomask and avoid economic losses, time losses and waste of human resources for enterprises.

[0005] To achieve the above and other objectives, a first aspect of this disclosure provides a marking pattern for placement within a dicing channel of a photomask. The marking pattern includes a first marking pattern, a second marking pattern, and a third marking pattern arranged sequentially along a first direction. The first and second marking patterns are located on opposite sides of a bare die area at the edge of the photomask along the first direction, defining the length of the bare die area along the first direction, and the first marking pattern is located within the peripheral area of ​​the photomask. The third marking pattern is located between adjacent bare die areas along the first direction and defines the spacing between adjacent bare die areas along the first direction.

[0006] In the above embodiment, since a marking pattern is set in the cutting channel of the photomask, the marking pattern includes a first marking pattern, a second marking pattern, and a third marking pattern arranged sequentially along the first direction. The distance between the first marking pattern and the second marking pattern determines the length of the bare die area in the photomask along the first direction, and the distance between the third marking pattern and the second marking pattern determines the spacing between adjacent bare die areas in the photomask along the first direction. Since the number of bare die areas in the photomask along the first direction is known before the marking pattern is set, after the first marking pattern, the second marking pattern, and the third marking pattern are set, the length of the bare die area in the photomask along the first direction, the spacing between adjacent bare die areas along the first direction, and the number of bare die areas along the first direction are all determined. Therefore, the length of the photomask along the first direction is also determined, and all the first direction features of the bare die area division in the photomask can be determined. When performing defect inspection on photomasks, the machine can automatically divide the photomask according to the set marking pattern to obtain a bare wafer area with a defined edge position. Compared with the traditional technology where the edge position of the bare wafer area needs to be manually defined for each photomask, the technical solution disclosed in this disclosure can not only accurately divide the photomask to obtain the bare wafer area, enabling the machine to perform defect inspection smoothly and avoiding missed defects on the photomask, thus reducing the economic losses of enterprises; it can also pre-set the corresponding marking pattern for each photomask, saving the waste of human and time resources caused by different definitions of the edge position of the bare wafer area for different photomasks in the traditional technology; in addition, since the edge position of the bare wafer area of ​​some photomasks is difficult to determine, the technology of obtaining the bare wafer area using the marking pattern provided in this disclosure can divide the bare wafer area of ​​the photomask more accurately and faster, improving the efficiency of the photomask inspection process.

[0007] According to some embodiments of this disclosure, the marking pattern further includes a fourth marking pattern, a fifth marking pattern, and a sixth marking pattern arranged sequentially along the second direction; wherein the fourth marking pattern and the fifth marking pattern are located on opposite sides of the photomask along the second direction, and the fourth marking pattern is located in the peripheral area of ​​the photomask; the sixth marking pattern and the fifth marking pattern are located between adjacent bare die areas along the second direction, and are used to define the spacing between adjacent bare die areas along the second direction, wherein the first direction is perpendicular to the second direction.

[0008] According to some embodiments of this disclosure, the marking pattern further includes a seventh marking pattern and / or an eighth marking pattern. The seventh marking pattern is located in the peripheral area of ​​the photomask and is located on opposite sides of the photomask along the first direction with the first marking pattern. The eighth marking pattern is located in the peripheral area and is located on opposite sides of the photomask along the second direction with the fourth marking pattern.

[0009] According to some embodiments of this disclosure, the minimum spacing between any one of the first, second, and third marker patterns and the adjacent bare film area along the first direction is greater than a first preset standard distance.

[0010] According to some embodiments of this disclosure, the minimum spacing between any one of the fourth, fifth, and sixth marker patterns and the adjacent bare film area along the second direction is greater than the second preset standard distance.

[0011] According to some embodiments of this disclosure, the first preset standard distance is 0.45μm-0.55μm.

[0012] According to some embodiments of this disclosure, the maximum line width of any one of the first marker graphic, the second marker graphic, and the third marker graphic is less than a first preset critical size.

[0013] According to some embodiments of this disclosure, the maximum line width of any one of the fourth, fifth, and sixth marker graphics is less than a second preset critical dimension.

[0014] According to some embodiments of this disclosure, the first preset critical size is 155nm-165nm.

[0015] According to some embodiments of this disclosure, the shape of the orthographic projection of any one of the first, second, and third marking patterns onto the upper surface of the photomask includes at least one of a circle, an ellipse, a ring, and a polygon.

[0016] A second aspect of this disclosure provides a photomask, including a photomask body and a marking pattern as described in any of the embodiments of this disclosure. The marking pattern is disposed within the cutting channel of the photomask body to define the boundary of the bare wafer area on the photomask body, so as to accurately divide the photomask to obtain the bare wafer area, enabling the machine to perform defect detection smoothly, avoiding the situation where defects are missed on the photomask, saving human and time resources, and improving the efficiency of the photomask inspection process.

[0017] A third aspect of this disclosure provides a photomask detection method for detecting whether a photomask in any embodiment of this disclosure has defects; the photomask detection method includes:

[0018] Acquire the detection image and the corresponding standard image of the bare area in the photomask;

[0019] Based on the comparison between the detected image and the corresponding standard image, it is determined whether the photomask has defects.

[0020] In the photomask inspection method described in the above embodiments, the accuracy of defining the edge position of the bare die area in the photomask is improved by using the marker graphics provided in any embodiment of this disclosure to define the edge position of the bare die area. This ensures that the corresponding positions of the inspection image and the corresponding standard image in the bare die area can be accurately compared, so as to accurately detect defects in the photomask. In traditional photomask inspection methods, different photomasks require manual definition of different bare die area edge positions for defect detection. Since the edge positions of the bare die area of ​​some photomasks are difficult to determine, errors in the definition of the bare die area edge positions and slow definition speed are prone to occur, which mislead the inspection equipment in determining the corresponding positions of the inspection image and the standard image. This results in the inspection equipment detecting a large number of defects in locations where there are no defects and / or missing the detection of real defects. At this time, it is necessary to redefine the edge position of the bare die area and then inspect the newly divided bare die area. This process will cause a lot of economic losses and reduce the inspection efficiency of the inspection equipment. The photomask detection method disclosed herein improves the accuracy and efficiency of defining the edge position of the bare die area, overcomes the shortcomings of traditional technology due to incorrect edge position definition and slow definition speed, and saves enterprises economic, human and time costs.

[0021] According to some embodiments of this disclosure, determining whether a photomask has defects based on a comparison between a detected image and a corresponding standard image includes:

[0022] Obtain the detection grayscale values ​​at different locations in the bare film area based on the detection image;

[0023] Obtain standard grayscale values ​​at different locations in the bare film area based on the standard image;

[0024] Calculate the difference between the detected grayscale value and the standard grayscale value at different locations in the bare film area, and determine whether there is a defect in the photomask based on the comparison result of the difference with the preset grayscale difference range.

[0025] According to some embodiments of this disclosure, determining whether a photomask has defects based on a comparison between the difference value and a preset grayscale difference range includes:

[0026] If the difference is within the preset grayscale difference range, the photomask is determined to be defect-free;

[0027] If the difference is greater than or less than the preset grayscale difference range, the photomask is determined to have a defect.

[0028] A fourth aspect of this disclosure provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the photomask detection methods in this disclosure. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a top view schematic diagram of a photomask and its marking patterns provided in one embodiment of the present disclosure;

[0031] Figure 2a A schematic diagram of the photomask defect detection results provided in one embodiment of this disclosure, showing an incorrect definition of the edge position of the bare wafer area.

[0032] Figure 2b A schematic diagram of the photomask defect detection results provided in one embodiment of the present disclosure, showing the correct definition of the edge position of the bare die area;

[0033] Figure 3 This is a top view schematic diagram of a bare wafer area and adjacent marking patterns provided in one embodiment of the present disclosure;

[0034] Figure 4 This is a top view schematic diagram of a marker graphic provided in one embodiment of the present disclosure;

[0035] Figure 5 This is a schematic flowchart of a photomask detection method provided in one embodiment of the present disclosure;

[0036] Figure 6 This is a schematic flowchart of a photomask detection method provided in another embodiment of this disclosure;

[0037] Figure 7 This is a flowchart illustrating a photomask detection method provided in yet another embodiment of this disclosure.

[0038] Explanation of reference numerals in the attached figures:

[0039] 1000, Photomask; 10, Raw Area; 20, Marker Pattern; 201, First Marker Pattern; 202, Second Marker Pattern; 203, Third Marker Pattern; 204, Fourth Marker Pattern; 205, Fifth Marker Pattern; 206, Sixth Marker Pattern; 207, Seventh Marker Pattern; 208, Eighth Marker Pattern. Detailed Implementation

[0040] To facilitate understanding of this disclosure, a more complete description will now be given with reference to the accompanying drawings, in which preferred embodiments of the present disclosure are shown. However, this disclosure may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure.

[0042] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, doping type, or portion from another element, component, region, layer, doping type, or portion. Therefore, without departing from the teachings of this invention, the first element, component, region, layer, or portion discussed below may be referred to as the second element, component, region, layer, or portion.

[0043] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as “below,” “under,” or “below” will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0044] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that when the terms “comprise” and / or “comprising” are used in this specification, the presence of the stated feature, integer, step, operation, element, and / or part is established, but the presence or addition of one or more other features, integers, steps, operations, elements, parts, and / or groups is not excluded. Meanwhile, when used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0045] A photomask, also known as a photomask, is used in the semiconductor chip manufacturing process to create patterns on a semiconductor using photolithography. To transfer these patterns onto a wafer, the photomask's working principle is similar to that of a photographic negative used to transfer an image onto a photograph. A photomask typically uses quartz glass as a substrate, on which a layer of chromium metal and photosensitive emulsion are deposited. The designed circuit pattern is then exposed onto the photosensitive emulsion using an electron laser. The exposed area is developed, forming the circuit pattern on the chromium metal, creating a photomask similar to a negative. This photomask is then used to project and position integrated circuits. An integrated circuit lithography machine then photo-etches the projected circuit. The manufacturing process generally includes: exposure, development, removal of the photosensitive emulsion, and photolithography.

[0046] In the information age, the urgent need for miniaturization, lightweighting, and integration of devices has greatly driven the development of microfabrication technology. Photolithography is currently the most widely used technology in the semiconductor component manufacturing industry. With the rapid development of large-scale integrated circuits and microstructure photonic devices, the requirements for the precision and resolution of photolithography are becoming increasingly stringent. However, due to the optical diffraction limit, the resolution of traditional photolithography has an insurmountable limit. The photomask is a crucial component in photolithography; it must be manufactured to perfection. All circuit elements on a silicon wafer originate from the layout, therefore, the quality of the photomask plays a key role in obtaining high-quality patterns in submicron photolithography. If photomask defects are not detected, they will be replicated onto the photoresist on the silicon wafer surface. Therefore, after the photomask is manufactured, it undergoes extensive automated testing to inspect for defects and particles. Photolithography is a core technology in semiconductor manufacturing, and the photomask is the mold for photolithography; therefore, defect detection of the photomask is a very important step in semiconductor processes. However, traditional photomask inspection methods involve manual operation to define the edge position of the die during photomask inspection. This can lead to inaccurate edge definitions, making it difficult to completely divide the photomask into preset sizes and quantities. This can cause machine testing anomalies, hindering the accurate detection of defects on the photomask and resulting in economic losses for the company. Furthermore, the definition of the die edge position varies for different photomasks, and the die edge position itself is difficult to distinguish, ultimately causing time and wasted human resources for the company. Therefore, this disclosure addresses the inaccurate and inefficient die edge position definition in traditional technologies by providing a marking pattern, a photomask, a photomask inspection method, and a medium. This improves the accuracy of die edge position definition during photomask inspection and avoids economic, time, and human resource losses for the company.

[0047] Please see Figure 1This disclosure provides a marking pattern 20 for placement within the cutting channel of a photomask 1000. The marking pattern 20 includes a first marking pattern 201, a second marking pattern 202, and a third marking pattern 203 arranged sequentially along a first direction (e.g., the ox direction). The first marking pattern 201 and the second marking pattern 202 are located on opposite sides of the bare die area 10 at the edge of the photomask 1000 along the first direction (e.g., the ox direction), defining the length of the bare die area 10 along the first direction (e.g., the ox direction), and the first marking pattern 201 is located within the peripheral area of ​​the photomask 1000. The third marking pattern 203 is located between adjacent bare die areas 10 along the first direction (e.g., the ox direction) and defines the spacing between adjacent bare die areas 10 along the first direction.

[0048] In the above embodiment, since a marking pattern 20 is provided within the cutting path of the photomask 1000, the marking pattern 20 includes a first marking pattern 201, a second marking pattern 202, and a third marking pattern 203 arranged sequentially along a first direction. The distance between the first marking pattern 201 and the second marking pattern 202 determines the length of the bare die region 10 in the photomask 1000 along the first direction, and the distance between the third marking pattern 203 and the second marking pattern 202 determines the spacing between adjacent bare die regions 10 in the photomask 1000 along the first direction. Since the number of bare die regions 10 in the photomask 1000 along the first direction is known before setting the marking pattern 20, after setting the first marking pattern 201, the second marking pattern 202 and the third marking pattern 203, the length of the bare die region 10 in the photomask 1000 along the first direction, the spacing between adjacent bare die regions 10 along the first direction and the number of bare die regions 10 along the first direction are all determined. Therefore, the length of the photomask 1000 along the first direction is also determined, and all the first direction features of the bare die region 10 in the photomask 1000 can be determined. When performing defect inspection on the photomask 1000, the machine can automatically divide the photomask 1000 according to the set marking pattern 20 to obtain the bare wafer area 10 with a defined edge position. Compared with the traditional technology, which requires manual definition of the edge position of the bare wafer area 10 for each photomask 1000, the technical solution of this disclosure can not only accurately divide the photomask 1000 to obtain the bare wafer area 10, enabling the machine to perform defect inspection smoothly and avoiding missed defects on the photomask 1000, thus reducing the economic losses of enterprises; it can also pre-set the corresponding marking pattern 20 for each photomask 1000, saving the waste of human and time resources caused by different definitions of the edge position of the bare wafer area 10 for different photomasks 1000 in the traditional technology; in addition, since the edge position of the bare wafer area 10 of some photomasks 1000 is difficult to determine, the technology of using the marking pattern 20 provided in this disclosure to obtain the bare wafer area 10 can divide the bare wafer area 10 of the photomask 1000 more accurately and faster, improving the efficiency of the photomask 1000 inspection process.

[0049] Please see Figure 2a and Figure 2bIn traditional techniques, when a photomask is divided into several bare wafers during defect detection, the process of defining the edge positions of these wafers is done manually. Operators manually mark each photomask to determine the edge position and length of the wafers in each direction. However, the size that the human eye can distinguish is not small enough, and manual operation is prone to errors. This method easily leads to inaccurate edge definitions, making it difficult to completely divide the photomask into the preset size and number, resulting in abnormalities in machine testing and inability to accurately detect defects on the photomask. Furthermore, different photomasks have different requirements, and the definition requirements for wafer edge positions vary. The edge positions of wafers in some photomasks are inherently difficult to distinguish, further increasing the difficulty for operators in setting marks, impacting both operation time and accuracy. Figure 2a The image shown is a defect distribution map of a photomask caused by an incorrect definition of the wafer edge position. In actual process operation, if the wafer edge position of a photomask is defined incorrectly, the photomask defect inspection machine will detect a large number of concentrated defects that do not actually exist. In this case, the wafer edge position must be redefined. Figure 2b The image displayed shows the distribution of photomask defects detected by the defect inspection machine after the die edge position was corrected. At this point, the die edge position was corrected, and many incorrectly detected defects disappeared, revealing only the actual defects of the photomask. Referring to this defect distribution map, further defect repair of the photomask can be performed. The entire process of correcting the markings after an incorrect die edge position definition and then performing defect inspection on the photomask significantly wastes machine capacity and affects inspection efficiency. In the long run, this will cause economic losses, time losses, and a waste of human resources for the company. Compared to the shortcomings of traditional photomask defect detection technologies, the marking graphics provided in this disclosure accurately locate the edge position of the die area in the photomask. Addressing the difficulty in determining the edge position of the die area in some photomasks, it more accurately divides the die area of ​​the photomask, enabling the machine to perform defect inspection smoothly, avoiding missed defects on the photomask, and allowing for pre-setting of corresponding marking graphics for each photomask, saving time spent manually setting markings for each photomask and improving the efficiency of the photomask inspection process.

[0050] As an example, please continue reading Figure 1The marking pattern 20 also includes a fourth marking pattern 204, a fifth marking pattern 205, and a sixth marking pattern 206 arranged sequentially along a second direction (e.g., the oy direction); wherein the fourth marking pattern 204 and the fifth marking pattern 205 are located on opposite sides of the photomask 1000 along the second direction (e.g., the oy direction), and the fourth marking pattern 204 is located within the peripheral area of ​​the photomask 1000; the sixth marking pattern 206 and the fifth marking pattern 205 are located between adjacent bare die areas 10 along the second direction (e.g., the oy direction), and are used to define the spacing between adjacent bare die areas 10 along the second direction (e.g., the oy direction). The first direction is perpendicular to the second direction.

[0051] As an example, please continue reading Figure 1 The marking pattern 20 also includes a seventh marking pattern 207 and / or an eighth marking pattern 208. The seventh marking pattern 207 is located in the peripheral area of ​​the photomask 1000 and is located on opposite sides of the photomask 1000 along a first direction (e.g., the ox direction) with the first marking pattern 201. The eighth marking pattern 208 is located in the peripheral area and is located on opposite sides of the photomask 1000 along a second direction (e.g., the oy direction) with the fourth marking pattern 204.

[0052] For example, please refer to Figure 1 and Figure 3 The spacing between the marker pattern 20 and the bare wafer area 10 is d. The minimum spacing d between any of the first marker pattern 201, the second marker pattern 202, and the third marker pattern 203 and the bare wafer area 10 adjacent to it along the first direction (e.g., the ox direction) is greater than a first preset standard distance. The first preset standard distance is 0.45μm-0.55μm, specifically, it can be 0.45μm, 0.48μm, 0.50μm, or 0.55μm, etc.

[0053] As an example, the minimum spacing between any of the fourth marker pattern 204, the fifth marker pattern 205, and the sixth marker pattern 206 and its adjacent bare wafer region 10 along the second direction (e.g., the oy direction) is greater than a second preset standard distance. This second preset standard distance can be equal to a first preset standard distance. Specifically, the second preset standard distance is 0.45μm-0.55μm, and can be 0.45μm, 0.48μm, 0.50μm, or 0.55μm, etc.

[0054] For example, please refer to Figure 1 and Figure 4The maximum line width of any one of the first marker pattern 201, the second marker pattern 202, and the third marker pattern 203 is less than a first preset critical size. In this embodiment of the present disclosure, the marker pattern 20 is annular, and the maximum line width w1, w2, w3, and w4 of any one of the first marker pattern 201, the second marker pattern 202, and the third marker pattern 203 is less than the first preset critical size. The first preset critical size is 155nm-165nm; specifically, the first preset critical size can be 155nm, 158nm, 160nm, 165nm, etc.

[0055] As an example, the maximum line width of any one of the fourth marker graphic 204, the fifth marker graphic 205, and the sixth marker graphic 206 is less than the second preset critical size. The second preset critical size can be equal to the first preset critical size. The second preset critical size is 155nm-165nm. Specifically, the second preset critical size can be 155nm, 158nm, 160nm, 165nm, etc.

[0056] As an example, during the photomask defect detection process, the maximum line width of any one of the first marker pattern 201, the second marker pattern 202, and the third marker pattern 203 must be less than the first preset critical size; the maximum line width of any one of the fourth marker pattern 204, the fifth marker pattern 205, and the sixth marker pattern 206 must be less than the second preset critical size. This is because when the line width of the marker pattern 20 is below the set range, the small marker pattern will be smaller than the resolution of the photolithography machine. Therefore, during exposure, these small marker patterns only scatter the light and will not be transferred to the photoresist. These small marker patterns are sub-resolution auxiliary patterns, or they can also be called scattering bars. At this time, the marker pattern only serves to define the edge position of the bare die area and will not affect the accuracy of pattern transfer during the photolithography process.

[0057] As an example, the orthographic projection of any one of the first marking pattern 201, the second marking pattern 202, and the third marking pattern 203 onto the upper surface of the photomask 1000 includes at least one of a circle, an ellipse, annulus, and polygon. Specifically, in the embodiments of this disclosure, the shapes of the first marking pattern 201, the second marking pattern 202, and the third marking pattern 203 are annulus.

[0058] As an example, this disclosure provides a photomask, including a photomask body and a marking pattern as described in any embodiment of this disclosure. The marking pattern is disposed within the dicing channel of the photomask body to define the boundary of the bare die area on the photomask body, thereby accurately dividing the photomask to obtain the bare die area. This allows the equipment to smoothly perform defect detection, avoids missed defects on the photomask, saves human and time resources, and improves the efficiency of the photomask inspection process. After detecting defects in the photomask, technicians can further repair the defects. Repair operations include laser chemical vapor deposition correction for missing fine chromium films and laser removal of excess chromium films, etc. After repairing the photomask defects, the photomask needs to be re-inspected to ensure that it meets quality indicators. Since chip manufacturing requires dozens of photolithography processes, each photolithography process requires a photomask, and the quality of each photomask affects the quality of the photolithography. During the photolithography process, a series of optical systems are typically used to project the pattern on the photoresist coating on the wafer according to a preset ratio. Due to certain equipment or process limitations in the manufacturing process, the pattern on the photomask cannot be completely consistent with the design image. That is, in the subsequent silicon wafer manufacturing process, manufacturing defects and errors on the photomask will also be introduced into chip manufacturing along with the photolithography process. Therefore, by using the photomask provided in this disclosure for pattern transfer, the accuracy of the pattern transferred to the wafer can be improved, thereby improving the yield and stability of the chip.

[0059] For example, please refer to Figure 5 This disclosure provides a photomask inspection method for detecting whether a photomask in any embodiment of this disclosure has defects; the photomask inspection method includes:

[0060] Step S100: Obtain the detection image of the bare wafer area in the photomask and the corresponding standard image;

[0061] Step S200: Based on the comparison results between the detected image and the corresponding standard image, determine whether there are defects in the photomask.

[0062] Specifically, detecting the presence of a photomask requires comparing the pre-defined photomask wafer area with a corresponding standard image. The standard image includes the photomask and the pre-defined wafer area within it. The edge positions of the wafer area and the wafer area to be inspected are the same. Therefore, by comparing the inspected image of the wafer area within the photomask with the corresponding standard image, the comparison result can be obtained. Judging the comparison result allows for the detection of defects in the photomask, enabling further processing of the photomask. Using this photomask inspection method improves the accuracy and efficiency of wafer edge position definition and avoids economic losses, time losses, and wasted human resources for enterprises.

[0063] Specifically, in the photomask inspection method described in the above embodiments, the accuracy of defining the edge position of the bare die area in the photomask is improved by using the marker graphics provided in any embodiment of this disclosure to define the edge position of the bare die area. This ensures that the corresponding positions of the inspection image and the corresponding standard image in the bare die area can be accurately compared, so as to accurately detect defects in the photomask. In traditional photomask inspection methods, different photomasks require manual definition of different bare die area edge positions for defect detection. Since the edge positions of the bare die area of ​​some photomasks are difficult to determine, errors in the definition of the bare die area edge positions and slow definition speed are prone to occur, which mislead the inspection equipment in determining the corresponding positions of the inspection image and the standard image. This results in the inspection equipment detecting a large number of defects in areas where there are no defects and / or missing the detection of real defects. At this time, it is necessary to redefine the edge position of the bare die area and then inspect the newly divided bare die area. This process will cause a lot of economic losses and reduce the inspection efficiency of the inspection equipment. The photomask detection method disclosed herein improves the accuracy and efficiency of defining the edge position of the bare die area, overcomes the shortcomings of traditional technology due to incorrect edge position definition and slow definition speed, and saves enterprises economic, human and time costs.

[0064] For example, please refer to Figure 6 In step S200, based on the comparison result between the detected image and the corresponding standard image, it is determined whether the photomask has defects, including:

[0065] Step S210: Obtain the detection grayscale values ​​at different locations in the bare film area based on the detection image;

[0066] Step S220: Obtain standard grayscale values ​​at different locations in the raw film area based on the standard image;

[0067] Step S230: Calculate the difference between the detected grayscale value and the standard grayscale value at different locations in the bare film area, and determine whether there is a defect in the photomask based on the comparison result between the difference and the preset grayscale difference range.

[0068] Specifically, after acquiring the detection image and the corresponding standard image of the bare wafer area in the photomask, the detection grayscale values ​​at different locations in the bare wafer area of ​​the detection image are obtained, and the standard grayscale values ​​at different locations in the bare wafer area of ​​the standard image are obtained. These two are compared. If a difference exists, the difference between the detection grayscale values ​​at different locations in the bare wafer area and the standard grayscale values ​​is calculated. After obtaining the difference, the comparison result with the preset grayscale difference range can determine whether the current photomask has defects. If no defects are found, the photomask proceeds to the next process operation; if defects are found, the photomask is repaired. Using the above photomask detection method can improve the accuracy and efficiency of defining the edge position of the bare wafer, and save the company's economic, time, and labor costs.

[0069] For example, please refer to Figure 7 In step S230, determining whether the photomask has defects based on the comparison result between the difference and the preset grayscale difference range includes:

[0070] Step S231: If the difference is within the preset grayscale difference range, it is determined that the photomask has no defects; if the difference is greater than or less than the preset grayscale difference range, it is determined that the photomask has defects.

[0071] Specifically, when determining whether the photomask has defects based on the comparison between the difference value and the preset grayscale difference range, if the difference value is within the preset grayscale difference range, it is determined that the photomask has no defects, and the next process operation is performed on the photomask. If the difference value is greater than or less than the preset grayscale difference range, it is determined that the photomask has defects, and the photomask is repaired. The repair operation includes laser chemical vapor deposition to correct the missing fine chromium film and laser removal of excess chromium film, etc. After the photomask defect repair operation, the photomask needs to be re-inspected to ensure that the photomask meets the quality indicators.

[0072] It should be understood that, although Figure 5 , Figure 6 and Figure 7 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Furthermore, although... Figure 5 , Figure 6 and Figure 7 At least some of the steps in the process may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but may be executed at different times. The execution order of these steps or stages is not necessarily sequential, but may be executed in turn or alternately with other steps or at least some of the steps or stages in other steps.

[0073] As an example, this disclosure also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the photomask detection method in any of the embodiments of this disclosure.

[0074] In the above embodiments, the marking pattern, photomask, photomask detection method, and medium, since the marking pattern is set within the cutting path of the photomask and is set before photomask defect detection, the machine can automatically divide the photomask according to the set marking pattern to obtain a bare wafer area with a defined edge position during photomask defect detection. Compared to the traditional technology where each photomask requires manual definition of the edge position of the bare wafer area, the solution provided by this disclosure not only enables precise division of the photomask to obtain the bare wafer area but also allows for pre-setting of the corresponding marking pattern for each photomask. This saves the waste of human and time resources caused by different definitions of the edge position of the bare wafer area for different photomasks in the traditional technology. In addition, since the edge position of the bare wafer area of ​​some photomasks is difficult to determine, the technique of using the marking pattern provided by this disclosure to obtain the bare wafer area can divide the photomask's bare wafer area more accurately and quickly, enabling the machine to perform defect detection smoothly, avoiding missed defects on the photomask, improving the efficiency of the photomask detection process, and reducing economic losses for enterprises.

[0075] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. Any references to memory, storage, databases, or other media used in the embodiments provided in this disclosure can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0076] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features of the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0077] The embodiments described above are merely illustrative of several implementations of this disclosure, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this disclosure, and these all fall within the scope of protection of this disclosure. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A marking graphic, characterized in that, Used to be set in the cutting channel of the photomask, including a first mark pattern, a second mark pattern and a third mark pattern arranged sequentially along a first direction; The first marking pattern and the second marking pattern are located on opposite sides of the bare die area at the edge of the photomask along the first direction, for defining the length of the bare die area along the first direction, and the first marking pattern is located within the peripheral area of ​​the photomask; The third marker pattern and the second marker pattern are located between adjacent bare die areas along the first direction, and are used to define the spacing between adjacent bare die areas along the first direction; wherein, The minimum spacing between any of the first, second, and third marker patterns and the adjacent bare wafer regions along the first direction is greater than a first preset standard distance, which is 0.45µm-0.55µm. The maximum line width of any one of the first, second, and third marker graphics is less than a first preset critical size, which is 155nm-165nm.

2. The marking graphic according to claim 1, characterized in that, It also includes the fourth, fifth, and sixth marker graphics arranged sequentially along the second direction; The fourth and fifth marker patterns are located on opposite sides of the photomask along the second direction, and the fourth marker pattern is located within the outer periphery of the photomask. The sixth and fifth marker patterns are located between adjacent die regions along the second direction and are used to define the spacing between adjacent die regions along the second direction, wherein the first direction is perpendicular to the second direction.

3. The marking graphic according to claim 2, characterized in that, Also includes: The seventh marking pattern is located in the outer periphery of the photomask and is located on opposite sides of the first marking pattern along the first direction of the photomask; and / or The eighth marker pattern is located within the peripheral area and is situated on opposite sides of the fourth marker pattern along the second direction of the photomask.

4. The marking graphic according to claim 2 or 3, characterized in that, The minimum distance between any of the fourth, fifth, and sixth marker patterns and the adjacent bare film area along the second direction is greater than the second preset standard distance.

5. The marking graphic according to claim 4, characterized in that, The maximum line width of any one of the fourth, fifth, and sixth marker graphics is less than the second preset critical size.

6. The marking graphic according to claim 1, characterized in that, The shape of the orthographic projection of any one of the first, second, and third marking graphics onto the upper surface of the photomask includes at least one of a circle, an ellipse, a ring, and a polygon.

7. A photomask, characterized in that, include: Photomask body; as well as The marking pattern according to any one of claims 1-6 is disposed within the cutting channel of the photomask body to define the boundary of the bare die area on the photomask body.

8. A method for detecting photomasks, characterized in that, The method is used to detect whether the photomask of claim 7 has defects; the method includes: Obtain the detection image and the corresponding standard image of the bare wafer area in the photomask; Based on the comparison between the detected image and the corresponding standard image, it is determined whether the photomask has defects.

9. The method according to claim 8, characterized in that, The step of determining whether the photomask has defects based on the comparison result between the detected image and the corresponding standard image includes: The detection grayscale values ​​at different locations in the bare film area are obtained based on the detection image; Obtain standard grayscale values ​​at different locations in the bare film area based on the standard image; Calculate the difference between the detected grayscale value and the standard grayscale value at different locations in the bare film area, and determine whether the photomask has defects based on the comparison result of the difference with the preset grayscale difference range.

10. The method according to claim 9, characterized in that, The step of determining whether the photomask has defects based on the comparison result between the difference and a preset grayscale difference range includes: If the difference is within the preset grayscale difference range, it is determined that the photomask has no defects; If the difference is greater than or less than the preset grayscale difference range, the photomask is determined to have a defect.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method described in any one of claims 8-10.

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